Top Four Reasons to Use Arc Thermal Spray

Top 4 Reason to Use Arc Thermal Spray

Arc thermal spray, also known as twin wire arc spray, is one of the older and simpler forms of thermal spray coating. Thermal spray technology has come a long way over the years, from spraying basic metals and simple alloys to, now, spraying extremely hard ceramics and carbides. These advances don’t mean that arc thermal spray is any less valuable. We’ll be the first to tell you that thermal spray isn’t the cure all so you can believe us when we say that each process has a specific fit in the coating world. Among many things, twin wire arc thermal spray is great for dimensional restoration, sacrificial corrosion coatings, custom alloy coatings, and bearing surfaces. 

Dimensional Restoration 

The most basic use of arc thermal spray is dimensional restoration. Rotating parts often experience surface erosion over time from rotating inside sleeves or collars. This creates problems when the parts wear out of round and become unbalanced. Not only is this noisy, but it can also decrease operating efficiencies and the vibration can cause damage to other machine components. Arc spray can be used to remanufacture the surface of the part, up to a quarter of an inch, and restore it to OEM specifications. This is great for many parts including pump shaft repair, print roll repair, or hydraulic cylinder repair; to name a few.

Pump Shaft Before Dimensional RestorationPump Shaft After Arc Spray Dimensional Restoration

Sacrificial Corrosion Coatings 

Another application of arc spray is sacrificial corrosion coatings. Using Aluminum and Zinc-Aluminum, arc spray can provide an anodic layer over steel. This layer can attract corrosion and keep the underlying surface protected. Arc spray coatings are also porous so they can accept sealants more readily than a regular carbon or tool steel surface, so parts stay sealed longer. 

Custom Alloy Coatings 

One advantage of arc spray that is unique to this thermal spray process is how the spray material is fed during application. The gun used to apply this type of coating feeds two separate wires, charging them negative and positive, and causing them to arc and melt. Compressed air then propels these molten droplets onto the surface of the part. Since it uses two wires, you can create custom alloys by feeding two different material wires. One example is carbon steel and bronze to create a more wear resistant bearing surface coating than plain bronze. You can also combine a 316 stainless steel with a Molybdenum wire to create an economically friendly anti-galling coating. There are many combinations that can be explored and engineered to fit the operating environment of the part. 

Twin Wire Arc Spray Gun Diagram

Bearing Surfaces 

The application of thermal spray to bearing surfaces using arc spray allows the use of many materials for softer bearing surfaces. Soft bearing surfaces are used to allow deformation so that the bearing area can accommodate small amounts misalignment. Arc spray can apply bronze, babbitt, brass, and aluminum bronze. Using thermal spray to apply these as coatings, as opposed to making the entire part from these materials, is not only more economical but has the added benefit of porosity. Like sealants, the porous surface more readily accepts lubricants and holds onto them longer. Arc spray bearing surfaces can also be removed and reapplied again and again when they get worn and no longer operate at peak performance. 

Affordable Wear and Corrosion Surface Solutions 

The purpose of any thermal spray coating is to keep your parts operating at peak performance for longer, whether that’s through preventative coatings or remanufacture. Arc spray offers many unique solutions and is one of the most affordable forms of thermal spray coating. So, whether you are struggling with corrosion or bearing area issues, arc thermal spray could be the solution you’ve been looking for. Contact us to see if arc spray, or one of our other processes, could be the solution you've been looking for.